Forum Discussion
Dataflow - different results between preview and later access
Hi , MS_fn
Thanks for your quick response! According to your description, this may cause by the ehance compute engine.
As searched, this function is mainly used to create a SQL cache to implement Query folding to increase the performance of dataflow.
Once the enhanced compute engine is enabled in the Power BI Premium capacity settings, and the dataflow settings and configuration (as illustrated above) dictate that the engine is used for a given dataflow, this is what happens:
（1）When the dataflow is refreshed, the Power Query for each entity is executed, and the output of the query is persisted in the dataflow’s CDM folder as CSV data and JSON metadata
（2）For any entity for which the enhanced compute engine is enabled, the output of the entity’s Power Query is also loaded into a table in a SQL database instance managed by the Power BI serviceAnd there is differnce about ""what exactly do you mean by supported queries?"":
And for more information, you can refer to if can help you :
Dataflows enhanced compute engine – will it fold? – BI Polar (ssbipolar.com)
Power BI dataflows enhanced compute engine - YouTubeThank you for your time and sharing, and thank you for your support and understanding of PowerBI!
Best Regards,
Aniya Zhang
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly
Community SupportHi , MS_fn
Thanks for your quick response! According to your description, this may cause by the ehance compute engine.
As searched, this function is mainly used to create a SQL cache to implement Query folding to increase the performance of dataflow.
Once the enhanced compute engine is enabled in the Power BI Premium capacity settings, and the dataflow settings and configuration (as illustrated above) dictate that the engine is used for a given dataflow, this is what happens:
（1）When the dataflow is refreshed, the Power Query for each entity is executed, and the output of the query is persisted in the dataflow’s CDM folder as CSV data and JSON metadata
（2）For any entity for which the enhanced compute engine is enabled, the output of the entity’s Power Query is also loaded into a table in a SQL database instance managed by the Power BI service
And for more information, you can refer to if can help you :
Dataflows enhanced compute engine – will it fold? – BI Polar (ssbipolar.com)
Thank you for your time and sharing, and thank you for your support and understanding of PowerBI!
Best Regards,
Aniya Zhang
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly
Hi v-yueyunzh-msft ,
many thanks for the information. I went through the provided links and links from there as well as many other similar resources and I think I do comprehend the aim of the query folding and using cached data to optimize the performance but the howto is further quite unclear and why it's resulting in my issue. Within the most ETL scenarios the cache-access will probably be working without resulting in unexpected results but if a certain order of measurements and records are mandatory for the wanted views there seems to be a need to disable this feature.
Now I won't to dive deeper into the matter and therefore I regard it as solved. Again, many thanks for your support.
Hey MS_fn,
Thanks for your post. I am facing the exact same issue and my enhanced compute engine is misbehaving, changing some seemingly random values in a specific column. It took me a while to troubleshoot the problem but turning it off since to have fixed it for now. Did you ever find out why this happens and how to avoid it?No it's not solved - neither this specific case nor the more general issue that a data-update to a dataflow (just clicking on the update-button within the workspace) results reliable in updated and correct data. It worked instead by opening the dataflow and saving it again and performing then directly afterwards the update.
I think this behaviour is related to the implemented caching-logic - which might need to be configurred in some way (maybe activating an incremental refresh would also trigger a real update) or maybe just completely disabled.
Currently I didn't dive deeper into the matter because it's only a side-project to evaluate if Power BI is an alternatively for our other reporting. At the moment it didn't look like as if Power BI as environment has enough capabilities in regard to a multi-layer ETL and analytics in the UI - at least for our current requirements.
